Multiple-chip technology is developed under the requirements of downsizing, weight-reduction, and performance-enhancement for electronic equipments. Enhancements of performances are achieved by organizing a plurality of semiconductor elements into a semiconductor device of a single package conformation, and/or by reducing area for installing the elements on an electronic equipment, and/or by utilizing shorter interconnect distances between respective semiconductor elements (see, for example, Patent Documents 1, 2 and 3).
Conventionally, a junction between a semiconductor element and a lead terminal of a lead frame is generally formed of a gold wire (see, for example, paragraph 0015 of Patent Document 3).
In addition, conventionally, encapsulations for semiconductor devices such as integrated circuits, diodes, transistors and the like are formed mainly with cured products of epoxy resin compositions for encapsulating semiconductor devices. In particular, an epoxy resin composition for encapsulating semiconductor device, which contain an epoxy resin, a phenolic resin-based curing agent, and an inorganic filler, and exhibits better thermal resistance and humidity resistance, is employed for integrated circuits. In recent years, requirements for epoxy resin compositions for encapsulating semiconductor chips, which are employed for encapsulating semiconductor elements, growingly become more severe, under a situation where the level of the integration of the semiconductor elements are increased year by year and the surface mountability of semiconductor devices is increased.
An application to the semiconductor device employing multiple-chip technology is one of the solutions for such severe requirements. Devices of the multiple-chip type, which particularly includes stacked layers of semiconductor elements, has a current path that is narrowly complicated, and therefore fluidization of the epoxy resin composition for encapsulating semiconductor chips in the molding process are considerably limited. Thus, a problem of poor filling of the epoxy resin composition for encapsulating semiconductor chips is generated.